Electrolyte disorders are classified to ICD-9-CM category 276, Disorders of fluid, electrolyte, and acid-base balance. This column focuses on abnormal potassium and sodium levels in the blood.

Hypernatremia
Hypernatremia (hyperosmolality; 276.0) is defined as an elevated sodium level in the blood that is more than 145 milliequivalents per liter. Hypernatremia results from a decrease of free water in the body rather than excess sodium. Therefore, physicians may document the term dehydration instead of hypernatremia. Dehydration is classified to code 276.51. If, however, dehydration is documented with hypernatremia, assign only code 276.0 per coding directives in ICD-9-CM.

Common causes of hypernatremia include inadequate water intake, inappropriate water excretion, and the intake of a hypertonic fluid. Symptoms include lethargy, weakness, irritability, and edema, and seizures and coma may occur in more severe cases. The treatment for hypernatremia is the infusion of a water solution containing 0.9% sodium chloride.

Hyponatremia
Hyponatremia (hyposmolality; 276.1) is a sodium concentration in the blood of less than 135 milliequivalents per liter and occurs when the sodium in the blood is diluted by excess water. Signs and symptoms of hyponatremia include nausea/vomiting; headache; confusion; lethargy; fatigue; appetite loss; restlessness; irritability; muscle weakness, spasms, or cramps; seizures; and decreased consciousness or coma.

Common causes of hyponatremia include the consumption of excessive water during exercise, diuretics, syndrome of inappropriate antidiuretic hormone (SIADH; 253.6), dehydration, diet, and congestive heart failure. Per coding directives, if dehydration is documented with hyponatremia, assign only a code for the hyponatremia (276.1). In addition, if the patient has SIADH and hyponatremia, only code 253.6 is assigned. Hyponatremia is an integral part of the SIADH and would not be coded separately (AHA Coding Clinic for ICD-9-CM, 1993, fifth issue, page 8).

Hyperkalemia
Hyperkalemia (hyperpotassemia; 276.7) is an elevated level of potassium in the blood above 5 milliequivalents per liter. Hyperkalemia may be caused from a consumption of too much potassium salt, the failure of the kidneys to normally excrete potassium ions into the urine, or the leakage of potassium from cells into the bloodstream. Symptoms of hyperkalemia include heart abnormalities such as arrhythmia or cardiac arrest. Hyperkalemia can be treated with a low potassium diet or Kayexalate.

Hypokalemia
Hypokalemia (hypopotassemia; 276.8) is a below-normal level of potassium in the blood of less than 3.5 milliequivalents per liter. Hypokalemia may be caused from an overall depletion in the body’s potassium or an excessive uptake of potassium by muscle from surrounding fluids. Hypokalemia is most commonly caused by the use of diuretics. Because of this, a physician may order an infusion of potassium chloride when the patient is receiving diuretics such as Lasix. This is done for preventative measures and does not mean that the patient has hypokalemia.

Although a patient with mild hypokalemia does not have any symptoms, moderate hypokalemia results in confusion, disorientation, weakness, and discomfort/cramps of muscles. Hypokalemia is treated with potassium supplements, potassium chloride, potassium bicarbonate, and potassium acetate.

Coding Notes
An abnormal lab value—either too high or too low—alone does not constitute a diagnosis. The physician has to document the condition. In addition, the documentation must also reflect one of the following before the diagnosis can be coded: clinical evaluation, therapeutic treatment, diagnostic procedure, extended length of hospital stay, or increased nursing care and/or monitoring.

It is the physician’s responsibility to document the patient’s diagnosis. In the inpatient setting, a diagnosis based on an abnormal lab result or diagnostic test should not be determined by someone other than a physician. The physician must document the diagnosis in the medical record before it can be coded. In addition, it is not adequate for a physician only to use arrows (Ý or ß) to indicate a diagnosis, even if treatment was given for that condition. For example, the physician documents “Na ß 129. Decrease fluid intake. Change IV fluids.” In this example, hyponatremia (276.1) could not be coded without the physician documenting it. Query the physician regarding the patient’s specific diagnosis.

Coding and sequencing for electrolyte disorders are dependent on the physician documentation in the medical record and application of the Official Coding Guidelines for inpatient care. Also, use specific AHA Coding Clinic for ICD-9-CM and American Medical Association CPT Assistant references to ensure complete and accurate coding.

— This information was prepared by Audrey Howard, RHIA, of 3M Consulting Services. 3M Consulting Services is a business of 3M Health Information Systems, a supplier of coding and classification systems to nearly 5,000 healthcare providers. The company and its representatives do not assume any responsibility for reimbursement decisions or claims denials made by providers or payers as the result of the misuse of this coding information. More information about 3M Health Information Systems is available at www.3mhis.com or by calling 800-367-2447.